Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : 
      11             : #ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_RW_LOCK_WRAPPER_H_
      12             : #define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_RW_LOCK_WRAPPER_H_
      13             : 
      14             : #include "webrtc/base/thread_annotations.h"
      15             : 
      16             : // Note, Windows pre-Vista version of RW locks are not supported natively. For
      17             : // these OSs regular critical sections have been used to approximate RW lock
      18             : // functionality and will therefore have worse performance.
      19             : 
      20             : namespace webrtc {
      21             : 
      22           0 : class LOCKABLE RWLockWrapper {
      23             :  public:
      24             :   static RWLockWrapper* CreateRWLock();
      25           0 :   virtual ~RWLockWrapper() {}
      26             : 
      27             :   virtual void AcquireLockExclusive() EXCLUSIVE_LOCK_FUNCTION() = 0;
      28             :   virtual void ReleaseLockExclusive() UNLOCK_FUNCTION() = 0;
      29             : 
      30             :   virtual void AcquireLockShared() SHARED_LOCK_FUNCTION() = 0;
      31             :   virtual void ReleaseLockShared() UNLOCK_FUNCTION() = 0;
      32             : };
      33             : 
      34             : // RAII extensions of the RW lock. Prevents Acquire/Release missmatches and
      35             : // provides more compact locking syntax.
      36             : class SCOPED_LOCKABLE ReadLockScoped {
      37             :  public:
      38           0 :   ReadLockScoped(RWLockWrapper& rw_lock) SHARED_LOCK_FUNCTION(rw_lock)
      39           0 :       : rw_lock_(rw_lock) {
      40           0 :     rw_lock_.AcquireLockShared();
      41           0 :   }
      42             : 
      43           0 :   ~ReadLockScoped() UNLOCK_FUNCTION() {
      44           0 :     rw_lock_.ReleaseLockShared();
      45           0 :   }
      46             : 
      47             :  private:
      48             :   RWLockWrapper& rw_lock_;
      49             : };
      50             : 
      51             : class SCOPED_LOCKABLE WriteLockScoped {
      52             :  public:
      53           0 :   WriteLockScoped(RWLockWrapper& rw_lock) EXCLUSIVE_LOCK_FUNCTION(rw_lock)
      54           0 :       : rw_lock_(rw_lock) {
      55           0 :     rw_lock_.AcquireLockExclusive();
      56           0 :   }
      57             : 
      58           0 :   ~WriteLockScoped() UNLOCK_FUNCTION() {
      59           0 :     rw_lock_.ReleaseLockExclusive();
      60           0 :   }
      61             : 
      62             :  private:
      63             :   RWLockWrapper& rw_lock_;
      64             : };
      65             : 
      66             : }  // namespace webrtc
      67             : 
      68             : #endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_RW_LOCK_WRAPPER_H_